The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Environmentally-friendly vehicles include fuel-cell vehicles, electric vehicles, plug-in vehicles, and hybrid vehicles. They typically have a motor for generating driving force.
A hybrid vehicle, which is an example of such environmentally-friendly vehicles, uses an internal combustion engine and battery power together. That is, the hybrid vehicle efficiently combines the power of the internal combustion engine and the electric power from the motor.
A hybrid vehicle may include an engine, a motor, an engine clutch that controls power between the engine and the motor, a transmission, a differential gear mechanism, a battery, a starter generator that starts the engine or generates power based on the engine's output, and car wheels.
Further, the hybrid vehicle may include a hybrid control unit that controls the overall operation of the hybrid vehicle, an engine control unit that controls the operation of the engine, a motor control unit that controls the operation of the motor, a transmission control unit that controls the operation of the transmission, and a battery control unit that controls and manages the battery.
The battery controller may be called a battery management system. The starter generator also may be called an ISG (integrated starter & generator) or an HSG (hybrid starter & generator).
The hybrid vehicle may operate in operation modes such as EV mode (electric vehicle mode), which runs the vehicle as a pure electric vehicle, powered solely by the motor, HEV mode (hybrid electric vehicle mode), which uses the engine's rotational force as main power and the motor's rotational force as auxiliary power, and regenerative braking mode, which recovers braking and inertial energy by the motor during braking or inertial driving and stores it in the battery.
A hybrid vehicle uses two power sources—that is, the engine and the motor, which constitute a variety of power transmission structures. Since the hybrid vehicle uses a motor using electrical energy, as well as the engine, the management of a state of charge (SOC) of the battery that stores electrical energy is important.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the present disclosure and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art.